1. Field of the Invention
The present invention relates to anti-theft devices used in automobiles in order to lock the steering.
2. Description of the Prior Art
Known anti-theft devices in general comprise a locking bolt actuated by a lock, which bolt may occupy two positions, i.e. an unlocked position in which the bolt is removed from the steering shaft and a locked position in which the bolt is located in a slot of a ring fixedly mounted on the steering shaft, which shaft is locked in this way. The bolt also occupies a third, intermediate, position in which it is supported on the periphery of the ring under the action of a spring. It is only when the end of the bolt is brought opposite the slot of the ring, as a result of rotation of the steering wheel, that the bolt extends into the slot under the action of the spring and locks the steering.
Tens of millions of these anti-theft devices for steering columns have been manufactured throughout the world and are mostly satisfactory from the point of view of security in operation. However, they have various drawbacks in use such as difficulty in unlocking the steering. Locking takes place, as mentioned above, by rotating the steering wheel in order to bring the bolt opposite the slot of the ring. When this has taken place, the bolt extends into the slot whilst the user continues to rotate the steering wheel until it locks. This then leads to a certain amount of wedging of the bolt in the slot which is further aggravated if the steering wheels abut against an obstacle (pavement, stone etc.). Unlocking therefore requires a considerable effort on the steering wheel before it is possible to actuate the unlocking key.